title: Bioassay-guided fractionation of extracts from Hypericum perforatum in vitro roots treated with carboxymethylchitosans and determination of antifungal activity against human fungal pathogens.
abstract: The aim of this study was to individuate, by bioassay-guided fractionation, promising antifungal fractions and/or constituents from Hypericum perforatum subsp. angustifolium in vitro roots. Treatments with chitosan, O-carboxymethylchitosan (CMC) and its derivatives were used to improve xanthone production in the roots. The bioassay-guided fractionation of CMC-treated roots led to the individuation of an ethyl acetate fraction, containing the highest amount of xanthones (6.8%) and showing the best antifungal activity with minimal inhibitory concentration (MIC) values of 53.82, 14.18, and 36.52 μg/ml, against Candida spp., Cryptococcus neoformans and dermatophytes, respectively. From this fraction the prenylated xanthone, biyouxanthone D has been isolated and represented the 44.59% of all xanthones detected. For the first time in the present paper biyouxanthone D has been found in H. perforatum roots and tested against C. neoformans, dermatophytes, and Candida species. The xanthone showed the greatest antifungal activity against C. neoformans and dermatophytes, with MIC values of 20.16, 22.63 μg/ml. In conclusion, the results obtained in the present study demonstrated that CMC-treated Hpa in vitro root extracts represent a tool for the obtainment of promising candidates for further pharmacological and clinical studies.
authors.affiliation: Department of Environmental Biology, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
authors.forename: Noemi
authors.initials: N
authors.lastname: Tocci
authors.forename: Felicia Diodata
authors.initials: FD
authors.lastname: D'Auria
authors.forename: Giovanna
authors.initials: G
authors.lastname: Simonetti
authors.forename: Simona
authors.initials: S
authors.lastname: Panella
authors.forename: Anna Teresa
authors.initials: AT
authors.lastname: Palamara
authors.forename: Aline
authors.initials: A
authors.lastname: Debrassi
authors.forename: Clovis Antonio
authors.initials: CA
authors.lastname: Rodrigues
authors.forename: Valdir Cechinel
authors.initials: VC
authors.lastname: Filho
authors.forename: Fabio
authors.initials: F
authors.lastname: Sciubba
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pasqua
mesh_terms: D000935:Antifungal Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects*; D048271:Chitosan / Q000031:analogs & derivatives* / Q000494:pharmacology; D003455:Cryptococcus neoformans / Q000187:drug effects*; D006801:Humans; D020902:Hypericum / Q000737:chemistry* / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry* / Q000187:drug effects; D054876:Prenylation; D044004:Xanthones / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000935:Antifungal Agents; C504164:O-carboxymethylchitosan; D010936:Plant Extracts; D044004:Xanthones; C586319:biyouxanthone D; D048271:Chitosan
keywords: Biyouxanthone D; Candida species Cryptococcus neoformans; Dermatophytes; St John's wort; Xanthone